The present invention relates in general to a method of forming emitter shapes of a field emission device. In particular, this invention relates to a method of directly forming emitter shapes or emitter-like shapes of a field emission device, and a method of forming emitter shapes on an original plate of a mold used in a transfer mold method.
With recent development of semiconductor fine-processing technology, attention has been paid to field emission devices which are micron-order fine vacuum tubes (electron guns) and the field emission devices have been widely developed.
In a proposed use of the field emission device, it may be employed as an electron emission source for an electron beam scribing apparatus or a planar display. For this use, many pointed emitter electrodes need to be arranged two-dimensionally wit high density. Where the field emission device is used as the electron emission source for the planar display, it is necessary to improve the sharpness of the pointed portion of each emitter electrode, thereby to decrease a drive voltage of the device.
There are following problems with the prior-art method of manufacturing the field emission device, as will be stated below.
In the prior art, emitter electrodes are pointed by means of superposing exposure or anisotropic etching using semiconductor fabrication technology. The reproducibility in the process of pointing the emitter electrodes is poor, and it is difficult to uniformly produce many emitter electrodes.
In this case, the degree of sharpness of pointed portions of emitter electrodes depends on the resolving power of the exposure apparatus. Although the degree of pointedness of emitter electrodes depends on the resolving power of a stepper, etc. for performing mask patterning, the resolving power is limited. Consequently, the enhancement of pointedness of emitter electrodes is limited.
And in the method of manufacturing the field emission device using the semiconductor fabrication technology, the size of a substrate on which the field emission device is to be formed is limited to the size of the semiconductor wafer.